Typically, to attach magnetic tape to the reels of a magnetic tape cartridge or cassette, the tape is cut perpendicularly to its longitudinal edges laterally across its width at each end. The ends are then attached to the reels of the cartridge and the tape is wrapped around the reels. Ideally, the tape wraps are perfectly smooth. In reality, a discontinuity exists on each reel along the lateral interface where the end of the tape attaches to the reel. The discontinuity causes an impression or imprint in the first few hundred tape wraps.
Data written on the longitudinally extending, parallel data tracks of the tape may not be consistently retrievable because the impression affects all of the data tracks at the same lateral location at the same time. This results in data errors. The severity of the errors may be such that the error correction code written on the data tracks to protect the data tracks cannot recover the data.
Similarly, servo information written on the longitudinally extending, parallel servo tracks of the tape may also not be consistently retrievable because the impression affects all of the servo tracks at the same lateral location at the same time. Thus, the servo redundancy cannot be used to recover the servo information. This results in servo errors and subsequent incorrect lateral positioning of the tape head with respect to the tape.
Tape impressions are a continuing problem in the data storage industry. Not using the portion of the tape with impressions results in wasted data storage capability and wasted time, as the tape must always be advanced past the unusable portions.
What is needed is a method of attaching tape to the reels of a cartridge such that impressions do not affect all of the data tracks and servo stripes at the same lateral location at the same time. The needed method must take advantage of the error correction code and servo redundancy such that data and servo information from the tape wraps may be consistently retrievable regardless of impressions.